YouTube Hits 100 Million

According to comScore, YouTube received more than 100 million unique visits in January, making it again the most widely viewed video service in the US.

The next four most-viewed video sites were Fox Interactive Media properties, Yahoo! sites, Microsoft sites and AOL, followed by the hard-charging Hulu.

YouTube owes much of its growth to the users who generate the majority of content on the site. eMarketer estimates that 9.1% of Internet users, or 18.1 million people, will create user-generated videos in 2009.

Despite this enthusiasm, YouTube has yet to fully realize its revenue potential.

"Even though YouTube continues to gain the most online video viewers, it barely monetizes those billions of monthly streams," said David Hallerman, senior analyst at eMarketer. "That underpeformance continues to leave the door open for its competition to take in more of the still-growing video ad revenue pie."

There are still gains to be made in the online video portal space.